The development of enzyme-amplified immunoassay systems will be pursued in three ways. Each of the systems will require no separation of antigen-antibody complexes from free antigen or free antibody and therefore should be readily adaptible to automation. The first approach will capitalize on the peroxidase activity of released hemoglobin in a microcomplement assay. The second will capitilize on the competition between peroxidase and catalase for substrate. The third will utilize the activation of peroxidase activity upon complexing heme with apoperoxidase. A method for the ablation of specific humoral and cell mediated immune responses in immunocompetent animals will be developed. A given antigen will be labeled with peroxidase and glucose oxidase. When the labeled antigen is in complex with the antigen-specific effector immunocytes, sodium iodide and glucose will be supplied. This should result in iodination of the effector cell and lead to the death of the cell, thus eliminating the specific immune response. This manner of control of immune responsiveness will be a great benefit to persons requiring tissue and organ transplantation and those with immunologic disorders.